pHoenix score: development and validation of a novel approach to decrease the number of inconclusive GERD diagnoses

The Johnson-DeMeester composite score (DMS) is the historical gold standard for diagnosing gastroesophageal reflux disease (GERD). The Lyon Consensus outlines criteria for diagnosing GERD by pH monitoring, defining normal acid exposure time (AET) as < 4% and pathological as > 6%, presenting diagnostic uncertainty from 4 to 6%. We aimed to (i) calculate the proportion of borderline studies defined by total AET alone that are reclassified as normal or pathological by the DMS, (ii) determine the importance of supine AET for reclassification, and (iii) propose a new classification system using a composite score that considers positional changes.